Oil pressure is critical for ensuring proper compressor lubrication; therefore, if zero or low oil pressure is detected, the unit must be shut down immediately for inspection. The potential causes and corresponding troubleshooting methods are outlined below:

Oil Piping Issues: Inspect the oil pump piping system connections for any leaks. Leaks prevent the oil pressure from building up; therefore, all joints should be tightened. Additionally, check the piping for any blockages; obstructions hinder oil flow and must be cleared.

Oil Pressure Regulating Valve Malfunction: If the oil pressure regulating valve is opened too wide or if its spool becomes dislodged, it will directly result in abnormal oil pressure. If the valve is improperly adjusted, readjust it to bring the oil pressure to the required level. If the spool has become dislodged, it must be reinstalled and secured.

Insufficient Crankcase Oil Level or Ammonia Contamination: If the lubricant level in the crankcase is too low, the oil pump will be unable to draw in a sufficient volume of oil; lubricant should be added immediately. If liquid ammonia has contaminated the oil, its subsequent evaporation can prevent the oil pump from drawing oil; in this case, the unit must be shut down to purge the ammonia before refilling the crankcase with fresh oil.

Oil Pump Wear: If the oil pump has been in service for an extended period and its internal clearances have become excessive, it may fail to generate adequate oil pressure. In such cases, the oil pump should be repaired; if the wear is severe, the pump should be replaced entirely.

Severe Wear of Moving Components: Severe wear on components such as connecting rod bearings, main bearings, connecting rod small-end bushings, and piston pins can result in excessive internal clearances, making it impossible to maintain oil pressure. The affected components must be replaced promptly.

Gasket Misalignment: If the gasket on the rear cover of the crankcase becomes misaligned, it may obstruct the oil pump’s intake passage. The cover should be removed for inspection, and the gasket’s position must be corrected and secured.

A decline in discharge volume is one of the most common issues encountered in natural gas compressors. The primary causes include:

Gas Valve Failure (Most Common Cause): Damaged suction or discharge valve plates, worn valve seat sealing surfaces, or failed valve springs can all lead to gas leakage and backflow, resulting in a significant drop in volumetric efficiency. Gas valves should be disassembled and inspected periodically, and any damaged valve plates or springs should be replaced.

Worn or Broken Piston Rings: As piston rings wear down, the clearance between the rings and the cylinder wall increases. This allows high-pressure gas to leak through the gap into the low-pressure side, resulting in increased internal leakage. A wear curve for the piston rings should be established, and the rings should be replaced periodically based on the accumulated operating hours.

Packing Gland Leakage: When the packing rings become worn, gas leaks outward along the piston rod. If a gas odor is detected within the compressor room, or if the packing gland vent port shows signs of continuous gas discharge, it indicates that the packing requires replacement.

Clogged Intake Filter: Excessive dust accumulation on the intake filter element increases suction resistance, leading to a drop in suction pressure and a reduction in the volume of intake gas. The filter element should be cleaned or replaced on a regular basis.

Excessive Clearance Volume: After prolonged operation, carbon deposits or wear on components such as the cylinder head covers and piston faces can increase the clearance volume, thereby compromising suction efficiency. This issue can be rectified by adjusting the clearance gaskets.

Insufficient Rotational Speed: Factors such as belt slippage, low motor voltage, or insufficient power frequency can cause the actual operating speed to fall below the rated speed, consequently affecting the discharge volume.

The operating parameters for an LPG compressor are subject to strict limits; if these limits are exceeded, immediate adjustment or shutdown is required:

Precautions:

Pressure gauges and thermometers must be checked at all times for signs of malfunction and subjected to periodic calibration.

During operation, monitor the machine for any abnormalities—specifically regarding stability, noise levels, temperature, and pressure.

Regularly drain moisture and oil from the gas-liquid separator and the pressure stabilizer tank; during this draining process, the system pressure should be maintained within the range of 0.294–0.392 MPa.

Many people mistakenly believe that a nitrogen compressor is merely a standard air compressor with a modified air intake; this is a serious misconception. The differences between the two are as follows:

Differing Purity Requirements: Processes within the electronics industry—such as SMT reflow soldering and chip packaging—require high-purity nitrogen with a purity level exceeding 99.999%. When a standard air compressor compresses air, oil vapors and moisture can contaminate the nitrogen, thereby compromising the wettability of solder joints. One semiconductor packaging and testing facility, for instance, experienced an increase in the rate of “cold solder joints” (poor connections) to 5.2% as a direct result of this issue.

Differing Material Requirements: Although nitrogen is an inert gas, it poses a risk of “nitrogen embrittlement” to carbon steel under high-pressure conditions. Consequently, the gas delivery system must be constructed using 316L stainless steel or higher-grade alloys; standard carbon steel piping is incapable of meeting these requirements.

Differing Sealing Standards: Nitrogen molecules are small and highly permeable; as a result, standard nitrile rubber seals are prone to premature aging and failure when exposed to nitrogen. It is therefore mandatory to utilize seals made from Polytetrafluoroethylene (PTFE) or perfluoroelastomer rubber (Kalrez).

Differing Leakage Rate Requirements: For high-purity nitrogen systems, the pressure drop across the entire unit during a 24-hour pressure-holding test must be less than 0.5%; this is a performance metric that standard air compressors are unable to achieve.

Gas pretreatment is a prerequisite for the reliable operation of a biogas compressor:

Desulfurization: Before entering the compressor, the biogas must undergo an appropriate desulfurization process (such as chemical absorption or biological desulfurization) to reduce its hydrogen sulfide (H₂S) content to a safe level (typically recommended to be < 50 ppm). The H₂S content in the biogas should be monitored regularly to ensure the effectiveness of the desulfurization process.

Installation of High-Efficiency Filters: High-efficiency filters must be installed upstream of the compressor’s inlet to remove solid impurities, oil residues, and other contaminants from the biogas. For biogas streams with high impurity levels, a multi-stage filtration system may be employed to enhance gas purity. The filter elements require periodic cleaning or replacement.

Dehydration: Reducing the moisture content in the biogas helps mitigate acidic corrosion caused by the dissolution of H₂S in water. Methods such as cooling-based water removal or adsorption drying may be utilized for this purpose.

Regular Monitoring: The composition of the biogas should be analyzed periodically, and pretreatment parameters adjusted as necessary in response to fluctuations in gas composition.